At a checkout counter in a store such as a supermarket, a queue for waiting for merchandise registration and the like is formed. Each customer intends to queue up for a checkout counter with a minimum waiting time, out of a plurality of checkout counters, by observing a length of each queue.
For example, PTL 1 describes a technology of recognizing merchandise by extracting an outline of the merchandise appearing in an image, and calculating and reporting a registration time.
PTL 2 describes a technology of obtaining and displaying a progress status of registration by measuring a weight of unregistered merchandise and a weight of registered merchandise.
PTL 3 describes a technology of detecting a number of customers in a queue or a length of a queue, and guiding a customer to a queue with a less waiting time.